Several cell-associated macromolecules implicated in the virulence of Streptococcus mutans are also found to be released into the growth medium. Among these are the glucosyltransferases, fructosyltransferases, and lipoteichoic acids. Preparations of these macromolecules, partially purified from the five serotypes of S. mutans, according to Bratthall, have been further characterized and compared both biochemically and immunologically. They are immunogenic in test animals and are currently being tested in rats to determine their effectiveness as a vaccine against dental caries. The present study proposes to highly purify these biosynthetic products and to further investigate their roles individually and in concert in the colonization and virulence of S. mutans. The purified preparations and various combinations of them will also be tested for their effectiveness, as vaccines, for their ability to protect against infection of Streptococcus mutans.